In The Secret World, there are three primary factions that feel as though they are meant to be based in reality: the Illuminati, the Templars, and the Dragon.
The Illuminati seems obvious. It's based on the real-world conspiracies of a secret organization that controls American politics, banks, and media. But because they are so "known" to us, that makes me assume that the other factions are meant to be known, as well. But I can't quite put my finger on it.
What exactly are the Templars? Knights? Crusaders? The game implies this is a faction that lives on to this day, but to my knowledge, they would have been long dead. There's even strong implication that the Illuminati and Templars once coexisted in Europe prior to the colonization of America.
What exactly is the Dragon? Yakuza? Triads? The game makes it clear that this is an Asian organization, but also attaches strong implications of mysticism which makes me wonder if they are based in reality, at all.
What "real-world" factions are the Templars and the Dragon based on? Are these fictional factions mostly real-world or mostly fantasy?
Also, if your evidence is spoiler-ridden, please refrain from including it. I will take your assertions as though they have evidence!